Dear Govardhan,

 UPESEAT exam has its difficulties in English and General Awareness while rest subjects are PCM whose level is somehow below or equal to JEE-Mains level.

now com your second question i.e how to prepare well:

you need primarily two things, knowledge of the basic concepts and how fast you can recall them. I would suggest just go through all the fundamental concepts of class 11 and 12, try to score atleast 45 out of 50 in the English+GK section and around 40 in PCM respectively which will take you around 165-170 marks and you can achieve your desired rank. Be calm during the exam and everything will fall in place.

hope you got your answer.

good luck  :)